The invention relates more particularly to a rechargeable battery pack having a supplementary electrical contact to engage with a contact on the recharging stand, and with which a mechanical locking device, by which the battery pack can be engaged securely with the power tool, is associated.
Rechargeable power tools are known. For example, rechargeable drills can have rechargeable batteries incorporated permanently therein, or can have removable battery packs. Power tools having removable battery packs are more versatile because several battery packs can be pre-charged for stand-by interchangeability during use of the power tool. That is, the tool needs not remain idle when its batteries are being recharged.
Power tools such as drills having replaceable battery packs, have various means of inter-engagement between the tool (usually at the base of the handle) and the battery pack. Such means serve not only to secure the components together mechanically, but also to provide proper electrical contact. When the battery pack is removed, it can be recharged. This can be achieved by attaching a wire from a mains-powered step-down transformer to the battery pack, or by mounting the battery pack itself on a recharging stand within which a step-down transformer is housed.
Many recharging stands have been proposed for this purpose. Some battery pack/recharging stand combinations have separate means of electrical and mechanical inter-engagement. Others have combined electrical/mechanical inter-engagement structures, but these can be more complicate in design and usability than might be desirable. For example, although a desirable feature is to securely lock the battery pack in place upon the power tool, it is not necessarily convenient to lock the battery pack securely in place upon the recharging stand.